Telephone system



Sept. 30, 1930. J'. wlcKs 1,777,062

TELEPHONE SYSTEM l Inuenm" Juhu Minka sept. 3o, 1930.

J. -wlcKs 1,777,062

TELEPHONE SYSTEM Filed March 9. 1927 2 Sheets-Sheet 2 [l Vini-LL xg l I I i L! "Jn-"IT m afm f2. I F l A; iol l L 11 Irrr Jahn Nicks Patented Sept. 30, 1930 UNITED STATES PATENT OFFICE JOHN WICXB, 0l OAI PABX, ILLINOIS, ASSIGNOB. TO RESERVE HOLDING COMPANY, Ol' KANSAS OITY, MISSOURI, A CORPORATION OF DELAWARE TELEPHONE SYSTEM Application led March 9, 1927. Serial No. 173,820.

The present invention -relates to telephone systems in general, but is concerned more particularly with improvements in the so-called toll service trunking system used by the toll operators in setting up toll connections to subscribers in automatic exchanges.

The general ob'ect of the invention is to produce a new an improved circuit arrangement for use in single-oiice automatic exchanges whereby the talking current for automatic lines involved in toll connections is supplied from the cord circuits at the toll board rather than from so-called transmission selector repeaters as has been done heretofore.

One object of the invention is the provision of arrangements whereby the ringing control conductor heretofore extending between the transmission selector repeater and the connector and used for starting the application of ringing current to the called line under the control of the toll operator is now extended back to the trunk circuit at the toll board and is controlled at that point by the toll operator. It is a feature of the invention that the manipulation of the ringing key by the toll operator after she has set up a toll connector controls the application of ground potential to the ringing control conductor over a circuit path independent of the talking conductors.

A further object of the invention is the provision of circuit arrangements whereby the calling device at the operators position is automatically connected to and locked into connection with the operators cord circuit when she momentarily operates her calling device push button and is subsequently automatically disconnected when the called line is tested and found to be idle.

A further object of the invention is the provision of means for informing the operator whether or not her calling device is connected with a cord circuit.

According to another object-of the invention arrangements are provided so that the cord circuit, bein normally arranged to operate with lines ot er than those extending to automatic switches, is automatically changed responsive to the operation of the calling device connecting key so that it will operate correctly to .set up a toll connection through the automatic switches and is maintained in the altered condition until the plug has been removed from the jack.

Referring now to the drawings comprising Figs. 1 and 2, they show by means'of the usual circuit diagrams so much of the apparatus in a telephone system embodying the features or' the inventlon as is necessary to an understanding of the invention.

Fig. l shows a two way'toll line incomin to the toll board and terminatin in the jac J1, the toll line having the usuai line equipment associated therewith. This .drawing shows also the cord circuit CC and the associated equi ment common to the several cord circuits. his cord circuit may be used for conecting a toll line with a toll service trunk, such as the one outgoing from the jack J 2 to the toll service trunking system. The righthand end of the cord circuit CC is arranged so that it will operate normally in connection with a regular manual line leading to a manual paystation, it being usual practice to provide a certain number of manual paystations terminating at the toll board in jacks and having the usual line equipment associated therewith. As such lines are old and well known they have been omitted from the drawing.

Fig. 2 shows the thousands selector TS, the hundreds selector HS, the connector C, and the automatic substation A accessible to the connector C. The connector C may be similar to the connector shown in my patent No, 1,633,149, granted June 21, 1927. The selectors are of the usual standard two-wire type, each having an extra conductor extending therethrough, the ringing control conductor.

The relay shown in the selectors is the usual switching relay.

The apparatus having been described generally, a detailed description of its operation will now be given. For this purpose it will be assumed that a call comes in over the toll line shown in Fig. 1 for the subscriber at substation A.

When thev distant toll operator projects ringing current over the toll line, the ring- Gul ing current flows through the upper winding of line lrelay 2, whereupon relay 2 operates and closes a locking circuit for its lower winding through the lower armature of cut-o relay 3. At its upper armature, relay 2 closes a ci-rcuit through the upper armature of cutoff relay 3 for the lamp 4 and a circuit for t-he mechanical supervisory signal 5 and its multiples in front of the other toll operators.

When the toll operator notes the lighted condition of the lam 4, she inserts the plug of an idle cord circuit, for example the lefthand plug of the cord circuit CC, into the jack J1. When this occurs, sleeve relay 3 in the trunk circuit operates over the sleeve of `the jack and the sleeve of the plug through the resistance 6 and the upper armatures of relays 7 and 8. Relay 3 unlocks and cuts oi the line relay 2, and it disconnects the line lamp 4 and closes a new circuit for the mechanical visual signals so as to maintain them operated after the line relay 2 has fallen back.

The operator now throws her key K1L into listening position and converses with the calling toll operator. Upon learning the number of the called subscriber, the answering toll operator restores her listening key and inserts the right-hand plu of the cord circuit CC into a jack associate with an idle toll line, the usual busy test being made by the toll operator prior to the restoration of the listening key. Assuming that the jack into which the plug is inserted is the jack J2,

relays 15 and 16, associated with the jack J 2, and relay 13 in the cord circuit operate in series. It will be noted that the sleeve resistance 12 is short-circuited at this time at the inner upper armature of relay 11. Relay 13 in the cord circuit CC prepares at its upper armature a lookin g circuit for the callingdevice-connecting relay 14, and closes at its lower armature a circuit for the supervisory lamp 18.

In the trunk circuit associated with the jack J2, relay 16 places ground on the release trunk conductor 22, thereby preparing a holding circuit for the automatic switches and a locking circuit for relay 17. Relay 15, at its lower armature, grounds the ringing control conductor 23 for a purpose to be explained hereinafter, and at its upper armature it places the lower Winding of relay 17 in bridge of the tip and ring contacts of the jack. When the plug has been fully inserted into the jack, current from the battery feed relay 10 in the cord circuit flows through the bridge including the lower winding of relay 17, whereupon relay 17 o erates and closes a locking circuit for itsel at its inner upper armature, and at its upper and lower armatures it disconnects its lower winding from across the talking conductors and connects the outgoing conductors 21 and 24 to the tip and ring contacts of the jack J.

When this occurs, the bridged line rela (not shown) of the thousands selector TS, ig. 2, operates in series with the battery feed relay 10 in the cord circuit, the upper winding of relay 10 operating over the upper talking conductor and a ground return circuit in series with the upper Winding of the line relay of the selector, such upper winding being connected to battery. A similar circuit is closed over the lower talking conductor for the grounded lower winding of the selector line relay and the lower wlnding of relay 10. Relay 10 opens the circuit of supervisory lamp 18 so as to prevent this lamp from lighting at this time. The thousands selector TS is prepared for operation in the usual manner by the energization of its above-mentioned line relay.

The operator now operates her push button P momentarily, thereby closing a circuit for the calling-device-connecting relay 14. Relay 14 operates and closes a locking circuit -or itself at its inner upper armature through the armature of relay 18 and the calling device lamp 1S). At its upper and lower armatures, relay 14 connects the calling device conductors to the tip and ring contacts of the associated plug, at the same time opening the talking conductors at this point. When this occurs the battery feed relay 10 in the cord circuit falls back, permitting the supervisory lamp 18 to become lighted again through the lower armature of the sleeve relay 13, but the line relay of the thousands selector TS remains energized through the polarized relay 18 and the remaining portion of the calling device circuit includin the secondary winding of the operators induction coil.

As a further result of the operation of relay 14, a circuit is closed for the connecting relay 11, whereupon relay 11 operates and locks itself at its lower armature to ground through the lower armature of sleeve relay 13. At its three upper armatures, relay 11 bypasses the normally closed upper springs of the ringing key K2 so that the upper talking conductor no longer extends through the said springs, and it transfers the shunt around the sleeve resistance 12 to the said normally closed contacts. In addition, relay 11 disconnects ringing current from the upper and lower contacts of the key K2 so that when the key K2 is subsequently operated the only effeet will be the opening of the lower talking conductor and the removal of the shunt from around the sleeve resistance 12 for a purpose to be subsequently explained.

When the operator releases the push button 3, the locking circuit through the lamp 19 becomes effective, whereupon the lamp 19 becomes lighted in series with relay 14 to remind the operator that her' calling device is now connected with a cord circuit. The polarized relay 18 is not operated at this time due to the direction in which it is polarized.

The operator now manipulates the calling device CD in accordance with the first di it in the number. The olf-normal springs o the calling device shunt the operators receiver so as to prevent disagreeable clicks as the lnterruptions are produced in the circuit upon the return of the calling device to normal. The thousands selector TS is raised opposite the level corresponding to the irst digit dialled, and it selects an idle trunk line, for example the trunk line extending to the hundreds selector HS.

When the second digit is dialled, the hundreds sclector HS responds by raising its wipers opposite the corresponding level and selecting an idle trunk extending to a connector, for example the connector C.

When the third and fourth digitsin the number are dialled the connector C raises its wipers opposite the desired level and rotates them into engagement with the bank contacts associated with the line of substation A. Assuming that the line is busy, the usual busy tone is placed on the talking conductors extending back to the toll board through the set up connection, whereupon the operator hears this tone as the dial circuit includes her head' set conductors. In this case the operator removes the plug from the jack J2 and allows the operated switches to release and subsequently makes another attempt to complete the connection.

Assuming that the called line is idle, this line is seized by the connector C and at the same time, the usual reversal of current flow in the trunk conductors incoming to the connector C is brought about by the connector whereupon the polarized relay 18 in the operators head set responds and opens the circuit of the lamp 19 and of the relay 14 in the cord circuit. The lamp becomes extinguished and relay 14 falls back, disconnecting the tip and ring conductors from the calling device circuit and reclosing the corresponding points in the talking circuit. Relay 10 of the cord circuit does not become operated in series with the line relay 'of the connector because the connections are now reversed in the connector C andthe line relay and battery feed relay are connected together, battery to battery and ground to ground.

In order to start the connector C to ringing the called line, the operator-operates her key K2 momentarily, thereby removingv the extended shunt from around the sleeve resistance 12 at the upper contacts of the ringing key. When this occurs, relay 15, connected in the sleeve circuit of the jack J 2, falls back momentarily and removes the ground from the ringing control conductor 23. Responsive to this operation, the ring-cut-off relay (not shown) in the connector C is unlocked and falls back, thereby applying the usual interrupted source of ringing current to the called line.

Relay 15 reoperates and reapplies' ground to the ringing control conductor when the shunt is again placed around the resistance 12 in the cord circuit, thereby again preparing the locking circuit for the above mentioned ring-cut-otl' relay.

When the subscriber at substation A responds to the ringing of his bell by removing his receiver, the ring-cut-oiiI relay in the connector operates and disconnects the ringing current source and extends the talking conductors through the manner shown by the dotted connections. Talking current is now supplied to substation A from the battery feed relay 10 in the cord circuit CC, and relay 10 operates and extinguishes the supervisory lamp 18 so as to give the operator answered supervision. A

As soon as the distant toll operator has connected the calling line to the toll line in the distant exchange the conversation may proceed in the usual manner.

When the subscribers replace their receivers at the end of the conversation, battery feed relay 10 in the cord circuit CC falls back responsive to the replacement of the receiver at substation A and relights the lamp 18 as a. disconnect signal.

When the distant toll operator receives the disconnect signal from the calling subscriber she projects ringing current out over the toll line, operating the clearing out relay 8 in the cord circuit CC. Relay 8 removes the shunt from around relay 7, whereupon relay 7 operates and opens a further point in the previously existing shunt and lights the lamp 9.

The operator, upon noting the lighted condition ot' the lamp 9, throws her listening key K1, whereupon relay 7 is again shunted and falls back, again closing its previously existing shunt from its own upper armature and the armature of relay 8. The lamp 9 is thereby extinguished. The two operators now converse and the operator at the cord circuit CC is instructed to take down the connection. When the plug is removed from the jack J1 sleeve relay 3 falls back, restoring the associated circuit condition to normal.

When the plug is removed from .the jack J2, sleeve relay 13 and relay 11 in the cord circuit CC fall back and the lamp 18 becomes extinguished. In the trunk circuit, relays 15 and 16 fall back, whereupon the established connection is released .in the usual manner by the removal of ground from the release trunk conductor 22 by relay 16.

When the operator at the cord circuit CC receives a ticket calling for a connection from a local line, for example the line of substation A, to a line reached over a toll line terminating in the jack J1, the procedure is much the same as that hereinbefore described except that the operator first plugs into the jack J2 and dials up the connection through the switches shown in Fig. 2 so as to cause the local line to be seized and made busy, but the llo operator does not throw her ringing key to signal the local subscriber until she has extended the connection to the desired line in the distant exchange. This is doneby inserting the left-hand plug of the cord circuit into the jack of an idle toll line, such as the jack J1, after which the operator projects ringing current over the toll line and instructs thc distant toll operator to set up the connection.

When the distant subscriber answers, the toll operator at the cord circuit signals the local subscriber by operating her ringing key with results'hereinbefore described.

In this case the operator at the cord circuit CC initiates the release when the local subscriber hangs up and brings in the disconnect lamp 18. The operator at once removes the plug from the jack J 2, but she operates her ringing key K1 to signal the distant toll operator over the toll line and instructs her to take down the connection, before she removes the plug from the jack J1. l

In case the operator wishes to use the righthand plug of the cord circuit CC to complete a connection to a manual toll line terminating in a jack at her position, the connecting relay 11 is not operated because the operator does not push the calling device push button I), and the cord functions as a regular common battery cord, ringing current being sent out over the tip and ring contacts of the righthand plug when the ringing key K2 is operated.

What is claimed is:

l. In a telephone system, means including a cord circuit at a toll board and an automatic switch controlled from said toll board for setting up a toll connection to a telephone line, connections in said automatic switch for supplying ringing current to the line, means controlled from said toll board for starting the application of ringing current to the line at the will of the operator at any time after the connection has been set up, and circuit connections in said cord circuit for supplying direct current to the connected line to energize the transmitter thereon.

2. Ina telephone system, means including a cord circuit at a toll board and an automatic switch controlled from said toll board to set up a connection to a called line, means at said toll board controlled by said switch for informing the operator thereat when a connection has been completed to said line, and circuit connections in said cord circuit for supplying direct current to said line t0 energize the transmitter thereon.

3. In a telephone system, means including a cord circuit at a toll board and an automatic switch controlled from said toll board to set up a connection to a called line, means at said toll board controlled by said switch for informing the operator thereat when a connection has been completed to said line, circuit connections in said cord circuit for supplying direct current to said line for 'talkin purposes, and means in said cord circuit or informing the o erator when the called subscriber respon s.

4:. In a telephone system, means including a cord circuit at a manual switchboard and an automatic switch for setting up a connection to a telephone line, a calling device at said switchboard for controlling said automatic switch, a key means responsive to the actuation of said ke for associating said calling device with sai automatic switch, and means associated with said calling device and controlled by a reversal of current in the talking conductors automatically effected by said switch upon the completion of its operation for disassociating said calling device from said switch.

5. In a telephone system, means includin a cord circuit at a manual switchboard and an automatic switch temporarily-connected thereto for setting up a connection-to a telephone line, a calling device at said switchboard, means for connecting said calling device to said cord circuit so as to enable said automatic switch to be operated by said calling device to set up said connection, means associated with said calling device and responsive to a current reversal brought about by said switch automatically upon the completion of its operation for disconnecting said calling device from said cord circuit, and means responsive to the disconnection of said cord circuit from said switch for renderinO the calling device connecting means in e ective in case the cord circuit is disconnected from said switch before said current reversal has taken place.

6. In a telephone system, means including 4a cord circuit for setting up a connection to a manual line and including said cord circuit and an automatic switch for setting up a connection to an automatic line, said cord circuit being normally in condition to set up a connection to said manual line, a relay con` trolled responsive to an incidental operation on the part of the operator at said switchboard when an automatic connection is being set up for conditioning said cord circuit for use in said automatic connection, and a locking circuit for maintaining said relay operated until the termination of the connection.

7. In a telephone system, means including a cord circuit for setting up a connection to a manual line and including said cord circuit and an automatic switch for setting up a connection to an automatic line, a ringing key in said cord circuit having alternating current leads associated therewith for supply-r ing ringing current over the talking strands of the cord circuit when the key is operated, a calling device for controlling the operation of said automatic switch, and means in said cord circuit automatically operated when the operator brings about the connectionof the calling device to the cord circuit to enable the automatic switch to be controlled by the calling device for disassociating said leads from the ringing key so that an operation thereof will not result in the projection of ringing current over the strands of the cord circuit.

8. In a telephone system, means including a cord circuit at a manual switchboard and an automatic switch controlled over one of the talking strands of said cord circuit for setting up a connection to a called line, said automatic switch being arranged so that it will not auoma-tically apply ringing current to the called line, and means controlled by the operator over a non-talking strand of said cord circuit for causing said switch to apply ringing currentto the called line.

9. In a telephone system, means including a cord circuit at a manual switchboard and an automatic switch controlled over one of the talking strands of said cord circuit for setting up a connection to a called line, said automatic switch being arranged so that it will not automatically apply ringing current to the called line, a ringing key in said cord circuit arranged to a ply ringing current to the talking strands o the cord circuit, means responsive to an operation of the ringing key for causing said switch to apply ringing current to the called line, and means automatically operated incidental to the control of the switch for preventing the said 'operation of said ringing key from resulting'in an application of ringing current to the talking strands of the cord circuit from said key.

10. In a telephone system, an automatic switch, a jack over which said switch is accessible, a plug ending cord circuit, a calling device, a sleeve relay operative responsive to the insertion of the plug of said cord into said jack, operator controlled means for connecting said calling device to said cord to place sald switch under the control thereof, a circuit including contacts on said sleeve relay for locking said calling device to said cord circuit independent of said operator controlled means, and means effective responsive to the completion of the operation of said switch for opening said circuit.

11. In a telephone system. a line, means including a cord circuit and an automatic switch for extending a connection to said line, signalling means in said switch for signalling over said line, and operator controlled means controlled over a non-talking conductor of said cord circuit for starting the operation of said signalling means.

12. In a telephone system, a line, means including a jacking ending trunk and an automatic switch accessible thereover for extendin a connection to said line, signalling means 1n said switch for signalling over said circuit is connected to said second line, a key,

means controlled by said key for causing signalling current to be applied to said talking conductors when said cord circuit is connected to said first line, and means controlled by said key for removing the potential on,

said non-talking conductor when said cord circuit is connected to said second line.

14. In a cord circuit having talking conductors and a non-talking conductor, a normally short-circuited resistance connected to one of said conductors, and a key eiiective when operated under certain conditions for applying signalling current to said talking conductors, and eiieetive when operated under certain other conditions for opening the short-circuit across said resistance.

15. In a cord circuit having a talking conductor and a non-talking conductor, means for establishing a current flow in said nontalking conductor, a key effective when operated under certain con-ditions for applying a characteristic potential to said talking conductor, andeifective when operated under certain other conditions for changing the value of the current ilow in said non-talking conductor.

16. In a cord circuit having a talking conductor and a non-talking conductor, means for establishing a current flow in said nontalking conductor, a key effective when operated under certain conditions for applying a characteristic potential to said talking conductor, and effective when operated under certain other conditions for changing the value of the current flow in said non-talking conductor, and means for preventing the application of said potential to said talking conductor when said key is operated under said certain other conditions.

17. In a telephone system, a trunk comprising two normally disconnected sections, means for seizing said trunk, arelay, means responsive to the seizure of said trunk for bridging said relay across the first section to lay for bridging said switching relay across l the first section to cause said switching relay to o crate, and means controlled by said switc ing relay for connecting said sections, for disconnecting said switching relay from the first section, and for establishing a holdlng circuit for said switching relay.

19. In a telephone system, means including a cord circuit for setting up a connection to a manual line and including said cord circuit and an automatic switch for setting up a connection to an automatic line, a ringing key in said cord circuit having connections associated therewith for suppl ringing current over the talking stran s 0% the cord circuit when the key is operated, a

calling device for controlling the operation of said automatic switch, means in said cord circuit automatically operated when the operator brings about a connection of the calling device to the cord circuit to enable the automatic switch to be controlled by the calling device for altering the connections associated with the ringing ke so that an op# eration thereof will not resu t in the proje@ tion of ringing current over the strands of the cord circuit, and means for maintaining the altered condition of the connections associated with the ringing key after the calling device has been disconnected from the cord circuit. i

In witness whereof, I hereunto subscribe my name this 2d day of March, A. D., 1927.

JOHN WICKS. 

